The present invention relates to an illuminative lamp disposed to illuminate the inside of a showroom or a front part of a showcase. The present invention more particularly relates to a showcase provided with an illuminative lamp having terminals at end portions.
Heretofore, in a showcase installed in a supermarket, a convenience store or the like, an illuminative lamp for illuminating the inside of a showroom, a front part of a showcase or the like is disposed in the showroom formed in a main body. The illuminative lamp is positioned and attached to a lower surface of a canopy positioned at a front part of a ceiling surface of the showroom, or a front part of a lower surface of a shelf in a case where a plurality of shelves are arranged. As the illuminative lamp, a fluorescent lamp or the like is generally used. Therefore, a replacement operation is required owing to deterioration with age.
Each illuminative lamp disposed in the showroom is connected to feeder lines connected to a power source disposed in a machine room (see, e.g., Japanese Patent Application Laid-Open No. 7-143928 (Document 1)). Since the illuminative lamp is attached to the front part of the showroom, the feeder lines are drawn and wired to an attachment position of the illuminative lamp, and fixed along the lower surface of the shelf or the ceiling surface. As shown in FIGS. 57 and 58, sockets 202 are attached to end portions of feeder lines 201. When terminals 204 disposed at end portions of an illuminative lamp 203 are attached to the sockets 202, the illuminative lamp 203 is electrically connected to the feeder lines 201, and electrically connected to a power source 205 via the feeder lines 201.
In this case, in consideration of an operability in attaching or detaching the illuminative lamp to or from the sockets connected to the feeder lines, the feeder lines in the vicinity of the sockets are fixed to the vicinity of an attachment place of the illuminative lamp in a state in which predetermined looseness is kept in the feeder lines. Therefore, in a state in which the illuminative lamp is attached, there has been a problem that, when the feeder lines sag downward from the lower surface of the shelf or the ceiling surface, the feeder lines are exposed on the front surface of the showroom, and an appearance is unfavorable.
Moreover, the illuminative lamp electrically connected to the feeder lines via the sockets is fixed by holding the lamp with clips or the like fixed to the lower surface of the shelf or the ceiling surface of the showroom. Especially, in a low-temperature showcase or the like which is internally cooled for use, to inhibit illuminance of an illuminative lamp such as the fluorescent lamp from being lowered owing to dependence on a temperature, a thermal insulation cylinder is mounted on the illuminative lamp. Therefore, since the long illuminative lamp attached to the showcase so as to range from side to side needs to be detached from or attached to a plurality of clips attached in a longitudinal direction, or detached from or attached to each socket during a replacement operation, there is a problem that the operation is troublesome.
To solve the problem, an attaching device of the fluorescent lamp is developed as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 5-69892 (Document 2) in order to simplify the above-described replacement operation of the illuminative lamp and prevent exposure of the feeder lines. This attaching device of the fluorescent lamp is constituted of a socket main body fixed to a lower surface of a shelf, and fluorescent lamp holders fixedly attached to the socket main body. The fluorescent lamp holders are attached to opposite ends of the fluorescent lamp provided with terminal pins for receiving power. When the fluorescent lamp holders are attached to the socket main body, the feeder lines are not loosened or exposed from the shelf lower surface, and the fluorescent lamp is attached to the shelf lower surface by only engagement of the fluorescent lamp holders with the socket main body.
However, in the above-described socket constitution disclosed in Document 2, the terminal pins for receiving the power come into contact with power supply contact pieces by use of elastic forces of the pieces themselves. In consequence, the pins are electrically connected to the pieces. Therefore, when the power receiving terminal pins are repeatedly inserted and disengaged, the elastic forces of the power supply contact pieces weaken, and there is a problem that contact defects are generated between the power receiving terminal pins and the power supply contact pieces. Such contact defects cause a disadvantage that the fluorescent lamp is not securely lit. In some case, temperatures of the power receiving terminal pins abnormally rise, and the terminal pins and the sockets might be burnt out.
Furthermore, in a conventional socket structure, the fluorescent lamp holders constituting the sockets are disengageably engaged with the socket main bodies by engagement of elastic pieces for bonding, formed externally from end surfaces of the fluorescent lamp holders on opposite sides with engagement pieces formed at the socket main bodies. In addition, when the fluorescent lamp itself is extracted downwards, such engagement is released. The fluorescent lamp holders are disengaged from the socket main bodies by applying a downward force. Therefore, when an attaching operation is repeatedly performed, engagement forces of these holders and main bodies weaken. In addition, there is an influence of a weight of the fluorescent lamp. Therefore, the fluorescent lamp attached to the sockets might fall together with the fluorescent lamp holders.
To solve the problem, such an engagement mechanism is constituted so that formed engagement members are fitted into each other in order to secure the mechanism. To disengage the members, the inwardly positioned engagement member is pressed inwards to release the engagement. However, in such a constitution, a large force for releasing the engagement has to be transmitted to the inwardly positioned engagement member, and there has been a problem of a troublesome operation.
Moreover, in the fluorescent lamp to be attached to the shelf lower surface, the ceiling surface of the showroom or the like, as shown in FIGS. 57 and 58, a capacitor 206 is electrically connected to the power source 205 disposed at a showcase main body via the connected feeder lines 201. In the sockets of the fluorescent lamp constituted as described above, the power receiving terminal pins of the fluorescent lamp can electrically be connected to the power supply contact pieces. However, the capacitor 206 is attached to a certain place of the showcase, and separately connected to the feeder lines connected to the power supply contact pieces. Therefore, wiring lines become complicated, and an operation of putting together the wiring lines has been troublesome.
On the other hand, to inhibit a disadvantage that heat of the fluorescent lamp leaks into the showroom, the fluorescent lamp holders of the conventional technology described above perform functions of support members to which a fluorescent lamp cover for thermal insulation is to be attached in order to inhibit a disadvantage that the illuminance of the fluorescent lamp drops in accordance with the temperature in the showroom. However, the support members of the fluorescent lamp cover formed at the fluorescent lamp holders are constituted by inserting cylindrical walls of the fluorescent lamp holders into the fluorescent lamp cover, the fluorescent lamp cover easily falls from the fluorescent lamp holders, and there has been a problem of a troublesome replacement operation of the illuminative lamp.
Furthermore, in a case where the showcase provided with the illuminative lamp is used as the low-temperature showcase, condensation is collected on the fluorescent lamp cover which surrounds the illuminative lamp itself and a periphery of the illuminative lamp, the condensation enters an electrically connected portion of the illuminative lamp, and short-circuit or the like might occur.